/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j.varia;

import org.apache.log4j.Logger;
import org.apache.log4j.BasicConfigurator;

import java.io.IOException;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.Socket;

/**
 * A simple application to send roll over messages to a potentially remote
 * {@link ExternallyRolledFileAppender}.
 * 
 * <p>
 * It takes two arguments, the <code>host_name</code> and
 * <code>port_number</code> where the <code>ExternallyRolledFileAppender</code>
 * is listening.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @since version 0.9.0
 */
public class Roller {

	static Logger cat = Logger.getLogger(Roller.class);

	static String host;
	static int port;

	// Static class.
	Roller() {
	}

	/**
	 * Send a "RollOver" message to <code>ExternallyRolledFileAppender</code> on
	 * <code>host</code> and <code>port</code>.
	 */
	public static void main(String argv[]) {

		BasicConfigurator.configure();

		if (argv.length == 2)
			init(argv[0], argv[1]);
		else
			usage("Wrong number of arguments.");

		roll();
	}

	static void usage(String msg) {
		System.err.println(msg);
		System.err.println("Usage: java " + Roller.class.getName()
				+ "host_name port_number");
		System.exit(1);
	}

	static void init(String hostArg, String portArg) {
		host = hostArg;
		try {
			port = Integer.parseInt(portArg);
		} catch (java.lang.NumberFormatException e) {
			usage("Second argument " + portArg + " is not a valid integer.");
		}
	}

	static void roll() {
		try {
			Socket socket = new Socket(host, port);
			DataOutputStream dos = new DataOutputStream(socket
					.getOutputStream());
			DataInputStream dis = new DataInputStream(socket.getInputStream());
			dos.writeUTF(ExternallyRolledFileAppender.ROLL_OVER);
			String rc = dis.readUTF();
			if (ExternallyRolledFileAppender.OK.equals(rc)) {
				cat.info("Roll over signal acknowledged by remote appender.");
			} else {
				cat.warn("Unexpected return code " + rc
						+ " from remote entity.");
				System.exit(2);
			}
		} catch (IOException e) {
			cat.error("Could not send roll signal on host " + host + " port "
					+ port + " .", e);
			System.exit(2);
		}
		System.exit(0);
	}
}
